Wearable absorbent articles are well known in the art. These articles typically have an absorbent core, which is held or positioned against the body of the wearer during use by a fastening system, such that the bodily exudates are caught by the article. Typical absorbent articles include a topsheet facing the wearer, which permits fluid exudates to pass through, and a backsheet which prevents the exudates from escaping from the absorbent article.
Much advancement has been made in the art since the introduction of the disposable absorbent article. However, problems still exist relating to the acceptance and storage of feces. The problem has been difficult to resolve because feces generally will not pass through a topsheet and thus, remains free to move about in the diaper until the diaper is changed. This often leads to feces escaping the diaper or soiling of the wearer's skin. In particular fluid feces has this problem, since it is very mobile on the topsheet and easily moves from one side to another and easy escapes the diaper's leg portions or leg cuffs.
In order to prevent the feces from escaping the absorbent article or soiling the skin, apertures have been provided in the top sheet, which allow the feces to pass to a void space disposed between the topsheet and underlying layers of the diaper. However, the apertures are difficult to position during application of the article and often move from the desired position when the article is worn.
Some degree of success has been achieved using an elastically foreshortened topsheet having a generally elliptical aperture to allow feces passage and retention away from the skin. These articles are disclosed in U.S. Pat. Nos. 4,892,536 issued to DesMarais and 4,990,147 issued to Freeland. These approaches have the limitation of not maintaining alignment of the opening with the wearer's anus in one or more of the longitudinal, lateral or z-direction axes of the article. Further, if the opening shifts laterally to a significant degree, the opening may achieve a geometric lock on the edge of the buttocks, decreasing the likelihood of proper aperture alignment with the anus.
Thus, it would be desirable to provide an improved absorbent article having an opening providing a passageway to a void space for receiving bodily exudates with improved fit and alignment capability which can be sustained during use, and which is such that the bodily fluids are more completely and effectively collected in said void space, or even such that about all solid fecal matter is collected in said void space.
The inventors have now found a way to solve this problem, by providing a topsheet containing elasticated regions which have a specific force profile and/or topsheets which have a specific elastic profile, and/or articles which have such a specific force profile through which they have a certain stretched and contracted length. The articles of the invention are such that the correct alignment is achieved when the article is first applied, independent on whether the article is applied correctly, and such that the correct alignment is remained in use. The article of the invention remain the correct alignment even when the wearer moves around, and even when the article is pulled down by the waist of the collected bodily fluids. The article has such an elastic profile that the slit opening remains located around the anus of the wearer, but also against the skin of the wearer, to reduce the risk that feces can escape to void space under the slit opening and to avoid the risk that the feces still moves freely on the topsheet and even leaks from the article.